The Big Bang Generator That Wasn't 220
ajs sent us a good investigative piece from the Boston Globe. Many of you recall the article about the Long Island particle accelerator that was going to try to replicate Big Bang conditions. Over the last three months, it's moved around the media, culminating with Fred Moody's scare piece about it, although the British Sunday Times recently picked it up yet again. The Globe article does a great job dissecting the actual facts behind the experiment and pokes fun at the growth of this Chicken Little-type story.
Art Imitating Life... (Score:2)
In Benford's vision, the universe created was seperate from ours, joined only by a "window" that exhibited itself as a mysterious black sphere about the size of a bowling ball, but massive. Most of the novel deals with the scientists solving the mystery of "what the hell is this thing?" Fun, hard, witty SF, with lots of scenes taking place in La Jolla, Pasadena, and Brookhaven.
Overall, very similar to Timescape, also by Benford. Also set at UCSD. Also about scientists. Also a great read.
You can also read the official report (Score:5)
sorry, no black holes or strangelets!
patrick.
None of this really matters (matter, get it...) (Score:1)
What if a black-hole does form? Ooohhh Myyyy Goooood!!!!!!!!! Then fwoop it doesn't matter anymore does it. Why? Well, everyone on earth would almost instantly be compressed into an infinitly small space. We're all dead and then nothing would matter anymore anyways....
Re:Gravity is still related to mass, so is momentu (Score:1)
But the sum of the momentum of the earth and the black hole must remain constant, so the black hole will actually slow down as it becomes more massive. Thus, if it isn't created moving at escape velocity, eventually we will wind up with a black hole with the same mass as earth in the same orbit around the sun.
*Neutron* accelerator?! (Score:2)
Correct me if I'm wrong, I'm not a particle physicist, but how would one accelerate neutrons?
Electrons: No problem, positive things atrract them, negative things repulse them.
Protons: Again no problem, just the inverse.
Neutrons: Dang! How the heck do you grab one of these things, anyway?
I know how neutrons can be generated by a nuclear reaction, etc., but fail to see how you could ever beam-ize the little turkeys once you've made them...
If this is possible, I'd love to know how it's done.
Re:Probability... (Score:1)
By the Intermediate Value Theorem, we see that the temperature must have been exactly 80.5 at some time between 3 and 5 PM. (Assuming that temperature behaves continuously, of course.)
Now, assuming that f is the probability density function for temperature in my area, the probability that the temperature is exactly 80.5 at any given time is
P(80.5 = T = 80.5) = int{80.5, 80.5} f(x) dx [1]
Since the limits are the same, the integral is zero (by FTC, re-take Calculus I for details).
The temperature *was* exactly 80.5 at some time today, yet the probability of it being so was zero."
OK, let's look at this.
The temperature, as you stated is not precise. Stating that the recorded temperature "is" a certain number really means that the temperature lies within a finite interval containing that number. Thus, a finite probability rather than a zero probability.
On the other hand, I would agree with you--provided that temperature is indeed continuous wrt time. However,this still leaves the problem of whether the temperature is exactly 80.5 for any finite amount of time. In order for this to be possible, clearly some nth derivative of the function is not continuous.
"P.S. I do not believe myself to be an idiot. (However, i do not have a proof of this.)
-- Mike"
I believe myself to be an idiot. (I just need to find one counterexample to disprove this. Sounds easier than your way.)
--Chris
Re:Probability... (Score:1)
Now we're starting down the road toward deep metaphysics. For instance:
1. If an event has a duration of zero, did it actually happen? What is the meaning of an instataneous measurement?
2. Since we cannot measure temperatures with ultimate percision, does it make sense at all to say that a temperature is exactly any number? Should a continuous random variable always be confined to a range?
3. Since temperature is a macroscopic phenomenon, does it make sense to apply ultimate percision to it at all? Would the concept of temperature disappear under infinitesmal scrutiny like length does? (See "How Long is the Coastline of Britian?", Benoit Mandelbrot.)
It was never my intention to launch a philosophical discussion. I was just trying to point out that the statement "Zero proability events can occur." is not idiotic. I can easily demonstrate such a case in mathematics, but whether or not you believe it happens in reality is a matter for your personal metaphysics.
"P.S. I do not believe myself to be an idiot. (However, i do not have a proof of this.)
-- Mike"
I believe myself to be an idiot. (I just need to find one counterexample to disprove this. Sounds easier than your way.)
--Chris
...and this of course get us into deep epistimology, the arguments hinging mostly on the definition of "idiot" and the possibility that a true idiot could convince himself that an invalid proof of non-idiotness was valid.
...but that's enough philosophy for today.
-- Mike
Re:Comfort (Score:1)
Fortunately, the Earth isn't dense enough for its gravity to smash the electron shells of the atoms at its core (unlike its larger neighbors, the Sun and Jupiter). Atoms at the Earth's core are only slightly more compressed than the ones at the surface, which means they're still basically empty space.A black hole of the mass we're postulating here couldn't possibly absorb enough mass in this environment to offset the virtual pair evaporation effect. Poof...no more black hole.
On a related note, if this experiment does produce a black hole (possibly), and it does evaporate (certainly), producing a flash of energy and heavy particles, will this be recorded on the scientists' instruments? And if so, will they publicize this? (Probably not...the mere _possibility_ that this experiment could produce a black hole has so many people in an uproar...imagine what the reaction will be if the scientists then say, 'Well, the experiment _did_ create a black hole...but it's nothing to worry about.'.
But enough about the hard science...we've all done the math (at least most of us have), and the the conclusion is obvious...we're not in danger of having a black hole eat the Earth (at least not from this experiment). What we _are_ in danger of is the hysteria that this Moody character is perpetuating. I particularly find this amusing in the context of the approaching Y2K debacle.
People have enough to be freaked-out about at this particular moment in history...there's no reason to throw gas on the fire.
Subtract a couple zeroes; it doesn't matter much. (Score:2)
That said, the numbers are not just huge. They are many orders of magnitude beyond huge. For instance, the megaton/m^2 flux at Mars is enough energy to blow off an atmosphere as thick as Venus'. 1 megaton = 4.2e22 ergs = 4.2e15 joules.
Nope. The gravitational energy available goes as 1/r, so a full 50% of the total is available from only 2 radii out. The radius of a 1-earth-mass black hole is about 1 centimeter; everything is going to be falling in from more than twice that!- Even at the equator, an object sitting on the ground has only enough angular momentum to maintain a circular orbit around an earth-mass point at 1/64 of the radius of the Earth. And that's the best an object on Earth can do! Things at the poles would fall straight down if they were suddenly unsupported.
- Conversion efficiency is supposedly up to 50%. All the mass cramming into that accretion disk at a large fraction of c generates a heck of a lot of heat.
- The mini-BH would fall from the surface of the earth toward the core (if it could last long enough to get out of the lab, which it could not), and as it absorbed mass it would also absorb the momentum of that mass. Unless there is a transfer of momentum, the center of mass of the system would remain on the same path. This means that the mini-BH would very quickly wind up stationary at the center of the Earth.
- Earth isn't very big, and doesn't have a lot of angular momentum compared to a star of far greater dimensions. If something swallowed the core, the rest would fall inward just fine.
The black hole couldn't starve unless the accretion disk could transfer enough angular momentum outward to get the remaining mass into orbit. Without that, the inward pressure of the falling mass would only be balanced by radiation pressure from the accretion disk. Since an object on the equator only has the angular momentum to maintain a circular orbit at 1/64 of an Earth radius, at least 99.9996% of the Earth would be able to fall into the BH unless prevented by other mechanisms. The jets are driven by radiation pressure. The jets will also be there to scatter the energy radiated poleward from the accretion disk and allow it to hit objects behind the accretion disk. Remember, my calculations only assumed that 0.0001 of the total energy escaped as radiation toward the equator. The same conclusions hold pretty much even if you reduce that to 0.00000001. See my previous comment about scattering efficiency and losses. I didn't say that Mars would be knocked out of orbit, I implied that the side facing Earth would be pretty thoroughly fried (a megaton/m^2 will do that). I'm pretty certain now that both Mars and Venus would lose their atmospheres (maybe only half of Venus, if the event went quickly).Were it possible for this to happen, the Solar system would not be a healthy place to be that day. It would be best to be somewhere far away on vacation, and deal with the insurance agent upon your return. And hope you have a "full replacement planet" policy. ;-)
--
Deja Moo: The feeling that
Re:Forever Peace (Score:1)
Re:certainty and artificial black holes (Score:1)
After Eon and Eternity, definitely I appreciate the warning...
Re:Gravity is still related to mass. (Score:1)
Re:Art Imitating Life... (Score:1)
Re:Probability... (Score:1)
But then the probability density isn't zero. In that case, you're not looking for the probability of a specific event, but of a range of events. Mind you, this is headed off-topic very quickly, but there are cases where even the probability density is zero--such as the probability density of finding a particle in the node of the corresponding wavefunction. The particle will never be found at such a location.
I see what you are saying, but this leads into studying the Surreal Numbers. Is a differential or infinitessimal probability the same as no probability? I think not.
Re:"strange matter" (Score:1)
The eternal search for truth and knowledge. (Score:1)
-Isaac Asimov
Re:Who are the Authors of that Piece? (Score:1)
Alright...what is "strange matter"? (Score:3)
thanks,
--Lenny
More on the authors (Score:2)
Swain [neu.edu]
Reucroft [neu.edu]
It's worth it (Score:1)
Interestingly depressing theory that Sagan had tho, that we can't find any ETI because they(we) always end up nuking them(our)selves.
It's either that or wait 5 billion years for Sol to engulf the earth in all it's gigantic red glory.
Chuck
Low probability and no evidence (Score:3)
It would be a black hole with a moon and satelites, some of them artificial.
And when physicists talk about "small but non-zero probablility" remember that there is a small but non-zero probability that a baseball-sized chunk of the Sun will appear on your desk within the next five minutes, due to quantum effects.
When these guys say "small", they mean it.
Fear my wrath, please, fear my wrath?
Homer
Re:Forever Peace (Score:1)
Re:Gravity is still related to mass, so is momentu (Score:1)
Re:Black holes (Score:1)
For links referring to a discussion on Hawking raditaion as well as the original paper which described it, see my first post.
Re:Subtract enuff zeroes; it does matter (Score:1)
Hehe, noted. You're welcome to have a beer anyway
But seriously:
That said, the numbers are not just huge. They are many orders of magnitude beyond huge. For instance, the megaton/m^2 flux at Mars is enough energy to blow off an atmosphere as thick as Venus'. 1 megaton = 4.2e22 ergs = 4.2e15 joules
Eye know about huge, I was just disagreeing how huge. Eating off zeros on the way.
Nope. The gravitational energy available goes as 1/r, so a full 50% of the total is available from only 2 radii out. The radius of a 1-earth-mass black hole is about 1 centimeter; everything is going to be falling in from more than twice that!
1.Even at the equator, an object sitting on the ground has only enough angular momentum to maintain a circular orbit around an earth-mass point at 1/64 of the radius of the Earth. And that's the best an object on Earth can do! Things at the poles would fall straight down if they were suddenly unsupported.
1/64 Earth radius is 10.000.000 Schwarzschild radii of an 1-earth-mass black hole (which does not exist at the time). I fail to see how it would find its way directly to the black hole (without an up-to-date inner-planetary map that is)
2.Conversion efficiency is supposedly up to 50%. All the mass cramming into that accretion disk at a large fraction of c generates a heck of a lot of heat.
Again I disagree. I'm not talking about forming a M-earth BH and subsequently letting testparticles fall into it. Only matter with small enuff angular momentum to hit the Kerr-radius directly will be eaten instantly. The earth will form an accretion disk extending from 100km to lets say a 100m, depending on radiation pressure. Free falling angular momentum carrying mass from 6000km out to 50km (not into the black hole!) speeds up to a small nowhere near a fraction of C. Your free-fall calculation does not include the centrifugal potential. Again our main difference is that I suggest that the accretion disk at the time of creation will contain almost all of the Earth's mass (lemme throw you a number 99.9999998%
3.The mini-BH would fall from the surface of the earth toward the core (if it could last long enough to get out of the lab, which it could not)...
Ofcuz. In our lively discussion I also forgot to stress that the damn thing would evaporate instantly anyway. This triggers another question, mebbe you can shed some light on this. How big must the progenitor BH be for the inbound mass flux (in the beginning dominated by free fall to the earth's center and the Rschwarz of the progenitor) to balance the evaporation mass flux?
4.Earth isn't very big, and doesn't have a lot of angular momentum compared to a star of far greater dimensions. If something swallowed the core, the rest would fall inward just fine.
Absolute ang momentum is irrelevant. Only the effective potential matters, and centrifugal component plays a crucial role. Earth spins about 30 times faster than the Sun.
The black hole couldn't starve unless the accretion disk could transfer enough angular momentum outward to get the remaining mass into orbit...
Now this is strange. Are you actually saying that angular momentum transfer helps the BH to starve? Or is there some wrong with my English? In standard thin disk accretion theory quasi-viscous ang momentum transfer is the only way to prevent it from starving. Accretion effeciency computed from the marginally stable orbit is only a few %. Bring in mind that the Kerr-radius is ridiculously small compared to the size of the accretion disk.
The jets are driven by radiation pressure. The jets will also be there to scatter the energy radiated poleward from the accretion disk and allow it to hit objects behind the accretion disk. Remember, my calculations only assumed that 0.0001 of the total energy escaped as radiation toward the equator. The same conclusions hold pretty much even if you reduce that to 0.00000001.
Two possibilities of Jet generation have been discussed in literature. The most important being magnetic field line winding and flux freezing wich will tend to make plasma stream along the field lines. It is thought that this dynamo-effect causes the bulk relativistic motion we call a jet. The radiation pressure only provide the initial acceleration to produce the outflow. That scattering on the jet will contriblute significantly to the overall radiation is unsupported by observations of real jets. My point is that given your severe overestimation of the radiated energy (calculated from a unrealistic simple scenario) and the chaotic poorly understood magnetic effects, the acretion scenario, the absorption of the dust band (which will be created) will provide anuff extra "couple of zero's" to topple your argument.
Especially the dust band is a nice one. The amount of extinction might be 100-300 magnitudes in UV/X-ray. I do not need to remind you what that means to the flux. But to all non-astrophysists: this means that only 0.00000000000000000000000000000000000001% of the radiation gets through. Ofcourse I'm not saying anything about the re-radiated IR radiation hehehheeh.
Love them zero's.
How 'bout a beer?
Ivo
Re:already happened? (Score:1)
As far as whether the conditions the RHIC is intended to reproduce have existed after the big bang, I'd refer you to an authoritative source, the RHIC web site [bnl.gov], which states:
So what they are saying is that perhaps the conditions only existed at the big bang, or perhaps they also exist in neutron stars. What they are NOT saying is that the conditions naturally occur anywhere nearby.You wrote:
As Arnold Rimmer would say: "Wrong, wrong, absolutely brimming over with wrongability."Re:certainty and artificial black holes (Score:1)
Re:Art Bell guest (Score:1)
Re:Subtract enuff zeroes; it does matter (Score:2)
- spun up from the contraction of its radius so that it achieves orbit, or
- blown off into a jet.
It'll find its way by gravitational attraction, and again you miss the point. It doesn't matter how many Schwarzchild radii that is; absolutely nothing on Earth could achieve an orbit farther out than that on its own angular momentum, so everything else would either be pushed into the BH by the pressure of the matter above it or blown off in one of the jets.About the best an object anywhere on the surface of Earth could do is to find an orbit at about 1/64 of its original radius (and that's the best). Since the volume of a sphere scales as r^3, chopping the radius of a sphere by 63/64 eliminates 262143/262144 of its volume. That's about 99.9996%.
I made no such assumption. I assumed only that any BH created at rest with respect to the surface of the earth would fall inward, and everywhere it went it would have plenty of matter to eat. As for the centrifugal potential, it would only make a difference if the angular momentum could not be dissipated against the matter further above. As angular momentum and energy are lost to friction, the matter spirals in. I have no idea. I've lost the equation for the evaporation rate of a BH, and since the Hawking radiation would tend to push things away the calculation is too complex for a simple discussion like this one. Now, if I were going for my PhD in physics I might do it as part of my thesis project, but I'm not. There's your error. You are assuming the matter is accreting from a thin disk (which is already in orbit). This assumption is not valid; it would be accreting from a nice, fat, spherical planet with a core of iron atoms at perhaps 10 grams/cc. To get to the thin-disk case, most of the planet would have to be either sucked down the BH or blown off in jets. Transfer of angular momentum outward works to give the remaining matter orbital velocity at a greater radius. It doesn't matter how small the Kerr radius is as long as there is a huge quantity of matter under pressure squeezing itself into the BH like water through a faucet. Ah. So you admit attempting to obfuscate the issue. Sorry, it doesn't win any points (or brew).Another model just occurred to me: the radiation pressure of the growing BH and its polar jets blows the remains of Earth into a boiling, seething mass of iron-silicate vapor. The heat from this melts the remaining artificial satellites and then coats them with molten goo, as well as stealing their angular momentum from gas drag and pulling them in to share the fate of their creators. The entire Moon gets coated in iron, which simultaneously obliterates all traces of Apollo and turns it into a shiny marble for the next several billion years. ;-)
--
Deja Moo: The feeling that
Re:already happened? (Score:1)
This is from a New Scientist article on the exact same topic (which was much more informative, by the way):
For those who want to read the article, you can find it at http://www.newscientist.com/n s/19990828/ablackhole.html [newscientist.com]. Its a month or two old, but I think it's much more informative than the one linked here. It rebukes the Sky Is Falling cries with more examples than the one at the Boston Globe.Before you call someone many different kinds of wrong, you may want to read up on it first. Our friend summed it up very well by saying it is "very old hat indeed."
Oops, missed a big one (Score:2)
--
Deja Moo: The feeling that
Re:Hmmmmmm ... (Score:1)
Re:certainty and artificial black holes (Score:1)
Re: A very slow Boom (Score:1)
Now that's not so nice...
Ah. So you admit attempting to obfuscate the issue. Sorry, it doesn't win any points (or brew).
Nah, just remembered that something had to happen to absorped energy. First effect is to puff up the dust donut. But after this it will loose energy in intense IR radiation, just as seen in the FIR galaxies.
Another model just occurred to me: the radiation pressure of the growing BH and its polar jets blows the remains of Earth into a boiling, seething mass of iron-silicate vapor...
Funny thing is that I was thinking 'bout the same thing on my way home yesterday. You know it is impossible that the Earth will collaps into the BH. This you must admit (altho you have been as stubborn as I am). Gravitational collaps with the outer matter pushing the inner matter without delay into the BH hole only works at a mass density close the critical value for a body to lie within it's own horizon. Direct formation of small black holes is extremely difficult.
Do you want a calculation? Critical density scales as M^-2 and has the density of 10g/cm^3 for a 10^7Msun Black hole candidate. For direct formation (collapse) of an Earth BH (Mearth = 3.10^-6Msun) you require a core density of roughly 10^24g/cm^3. This cant be obtained, at least not with our type of matter.
Therefore we need to have some sort of accretion scenario. Since we have spherical symmetrical mass distribution the maximum accretion speed is defined by the Eddington limit, where radiation pressure of the infalling inner layer and the pressure of the layer just outside it balance (in this scenario dominated by the pressure of the rest of the Earths mass above it). This effect starts immediately, and will generate the pressure to support the rest of the core and prevent it from collapsing. If you dont believe this, check every standard literature on gravitational collapse, black hole formation and Eddington accretion. Blowing off the outer layers is a possibility, but this requires super-Edington accretion (achievable in highly anisotropic situations), since you need more outward radiation pressure than supplied by the default balanced influx.
Eddington accretion and Lifetime:
There exist a maximum luminosity that can be radiated by a gravitating body of mass M. This limit arises because radiation pressure from a central source can not exceed the gravity of the infalling material and the excess pressure from the material above it (then it would starve). Although the actual value for the Luminosity is hard to calculate, because of the complicate environment in the earth's core, it is interesting to note that the lifetime of een object radiating at the Eddington limit is independent of mass. The lifetime (know as the Salpeter time) is proportional to Mc^2/Ledd and for silicate particles this might be anyware between 10^6-10^8 years. 10^8 for free-fall, 10^6 for solid object.
I suppose my story sounds a bit dull compared to the spectacular 'blowing the face of the moon' scenario, but I think that you will study the relevant literature you find that direct collapse is impossible.
I admit that some of my earlier objections were wrong, but hey they came only from the tip of my hat.
The problem is that altho your total total energy budget might be correct (within a factor of 1000 or so), your calculations about the effects on the moon need this energy to be released almost instantly. From the Salpeter lifetime however it is more likely that this will take millions of years. This is supported by all observations of actual BH and AGN canditates. Eye know that the actual accretion scenarios are different, but that is accounted for by taking enhanced isotropic accretion with silicate particles. (else you would end up with typical 10^12 yr lifetimes)
The heat from this melts the remaining artificial satellites and then coats them with molten goo, as well as stealing their angular momentum from gas drag and pulling them in to share the fate of their creators. The entire Moon gets coated in iron, which simultaneously obliterates all traces of Apollo and turns it into a shiny marble for the next several billion years.
Hehe, I must say that IS an actractive and esthethic thought. But again this requires extreme super-Eddington accretion and this is difficult to achieve.
My best guess is that the BH settles in the Earth's core, slowly accreting the mass because of the inevitable balance between radiation pressure and infalling material (pressure by the outer-layer does not change this, only the increases required radiation level and speeds up the lifetime by a million or so). The heat would slowly dissipate through to the Earth crust, making global warming more like global cooking. The seas will evaporate, we will melt. The Earth might resemble Venus within a few 1000 years. However I think that given the fact that the total radiated energy is smeared out over millions of years, the Moon for example will be able to keep kewl, just by thermal equilibrium.
Damn, got a dry mouth. Could use a beer tho.
Ivo
Ever wonder... (Score:1)
really bad happen?
doomsday weapon (Score:1)
One might not even need a way to target or limit its power. The point of a doomsday weapon is not to detonate it, but to get the other guy to give you what you want out of fear that you will detonate it. In all honesty, you don't even need to have the weapon, you just have to convince the other guy that you not only have it but are willing to use it. Even if it kills you.
It's the logic of people who hold up convenience stores with unloaded guns, and of people who strap explosives (or things that look like explosives) to themselves in order to get something they want.
Re:Long Islander Voices Opinion (Score:1)
(In all honesty, your drinking water is probably more messed up by industrial dumping over the years than it ever was from the Brookhaven Lab's modest program).
Re:The right answer(s) (Score:1)
Imagine the Earth and the sun as they are now. Then replace the sun with a blackhole (minus the whole supernova thing, though that wouldn't happen with our sun, which is why it won't become a blackhole). The gravitational pull would the the exact same on the Earth when it's orbiting the sun as a star, then it would be when it's orbiting a blackhole (life as we know it would die off without sunlight, but that's a different story). It's still the same amount of mass, it just has infinite density.
But if Tesla were running this experiement... (Score:2)
GunBuster. (Score:1)
Yes, there's a whole backstory, plot, and angst behind the show--go watch it.
Re:already happened? (Score:1)
life is like Slashdot! (Score:2)
Re:Alright...what is "strange matter"? (Score:1)
Ah...I needed a good laugh. (Score:2)
It seems ~90% of Slashdot readers side with the scientists, but I wonder if there isn't a real concern here. This is something that you would have to be a scientist just to make a judgement on, though, so I suppose we are stuck with their discretion, whether we like it or not. Let's just hope that they aren't Mad Scientists!
--Lenny
Re:Alright...what is "strange matter"? (Score:3)
Ondinary particles in the atomic nucleus (neutrons and protons) consist only of up quarks and down quarks. The other types of quarks may be produced in high-energy collisions, however.
IIRC, Strange matter is composed of these other types of quarks. In general, these particles are unstable and sooner or later (usually MUCH sooner) turn into normal quarks, giving off radiation in the process. Some people still worry about some chain reaction where strange matter converts normal matter into more strange matter, but I find this highly unlikely.
Earth is constantly bombarded by muons (related to electrons like strange quarks are to up quarks) and hasn't imploded on itself yet, even after billions of years. I really doubt we'll succeed in the 0.00000000000000000000003 seconds the collisions in the accelerator will last.
Someone really smart may be able to answer this... (Score:1)
Wouldn't it make sense that, these black holes out there would eventually all converge together, gaining mass and 'size', presumably even increasing escape velocity?
Can someone explain why this hasn't happened yet? Or let me know exactly when it will happen.
Re:Monkey Science (Score:1)
good article, bad reassurance (Score:1)
I liked some of the points made, but a couple of sentences sent chills up my spine:
Would that we could, but we can't, any more than you can make a black hole by shooting two billiard balls together.
this reminds me of the PATOS (PATEOS?) from Zodiac, as in: "by using a down-to-earth metaphor, we'll displace all your silly, uninformed fears"
From a theoretical viewpoint then, the risk of catastrophe is probably negligible.
I think it's the wording of this that gets me. "probably negligible"? I know I'll sleep well tonight because the PR flacks have told me not to worry about it.
phew, what a pity :((( (Score:1)
A very slow Boom, conceded! Time for beer! (Score:2)
As for the "seething ball of iron silicate" scenario, if energy could be transferred outward fast enough (say, from convection outside of the radiative zone) this would be possible, but you appear correct that this requires a rate of heat generation too high for a mini-BH to manage by accretion. Even if all of 3e-9 kg/sec was converted to energy, this would only yield 2.7e10 watts, or about the solar energy falling on 20 km^2 of the top of the atmosphere. A trifling amount. Next mystery: What would a decaying mini-BH (say, 1 million tons) do if it happened to be inside a planet when it went boom?
That was educational. Pitcher of Heineken?
--
Deja Moo: The feeling that
Re: Time for beer! Make that 2 ;-p (Score:1)
I think it would act like my thesis advisor, who was a bit upset that I missed a deadline because of this discussion, hehehe.
That was educational. Pitcher of Heineken?
Agreed. Make that 2
Ivo
Did nobody here read _Cosm_? (Score:1)
But basically, it's an entire book about exactly this issue. And much better done.
http://www.amazon.com/exec/obidos/ASIN/03807905
Re:Probability... (Score:1)
Events of probability zero can occur. In fact some of them happened today.
Proof:
Checking the weather data for my city, i see that at 3 PM, the temperature was 82 F, and at 5 PM, it was 79 F. These are not exact values, so let us assume that the temperature was between 81 and 83 at 3 PM and between 78 and 80 at 5 PM.
By the Intermediate Value Theorem, we see that the temperature must have been exactly 80.5 at some time between 3 and 5 PM. (Assuming that temperature behaves continuously, of course.)
Now, assuming that f is the probability density function for temperature in my area, the probability that the temperature is exactly 80.5 at any given time is
P(80.5 = T = 80.5) = int{80.5, 80.5} f(x) dx [1]
Since the limits are the same, the integral is zero (by FTC, re-take Calculus I for details).
The temperature *was* exactly 80.5 at some time today, yet the probability of it being so was zero.
Thus, event of probability zero can happen.
(This is hardly a rigorous proof. I have assumed several things, including the assumption that temperature is not quantized, but i hope the point is taken.)
-- Mike
P.S. I do not believe myself to be an idiot. (However, i do not have a proof of this.)
-- Mike
[1] p 131 _Probability and Statistics for Engineering and the Sciences_, Jay L. Devoe, Brooke/Cole 1991.
Re:Someone really smart may be able to answer this (Score:1)
What's a "dire consequence" to the universe? (Score:1)
Fortunately, nature has been doing just these sorts of experiments planned at RHIC for a long time and the universe is just fine.
Umm... I'm sure the universe itself didn't suffer dire consequences, but then, what's another black hole to the universe?
I think the point is that while a black hole or two might not devistate the universe as a whole, it would be bad for any populated planets in the area.
W
-------------------
In defense of my posting... (Score:1)
Okay, now that I'm done with the prefacing statements:), I'll deal with your objections.
the objections do not come from left field
Actually, in this case they do. There is only a very small probability that a Very Bad Thing will happen. And in this case, as in every quantum mechanical case, a very small probability is like the probability that a football-sized chunk of the Sun suddenly could appear on one's desk. Yes, it could happen, but don't hold your breath.
And human history is filled with enough follies by people who "know what they're doing"
Oh my, do we have a logical fallacy here? Why yes, boys and girls. It's our old friend, the argumentum ad hominem. Just because authority figures screwed up in the past (and in Challenger's case, it was bureaucrats who pushed the launch; the engineers, I believe, knew it probably wasn't safe to launch the shuttle), doesn't mean we can discount what they say now. We're also bordering on a conceptual slippery slope here. Just so you know.
Fianlly, your whole opening could be construed as the start of a strawman attack on my argument. By giving unimportant parts of my posting with which you find fault such prominence, you aare implicitly trying to discredit the rest of my post. Let's stick to the facts from now on, shall we? Yes, and avoid further rhetoric? Thanks so much.
It's just something else... (Score:1)
...for all the naysayers and religious wackos (hey, not saying anything again religion, just the people who take it too far) to point to and say that Jesus is coming back, or the alien space ship is behind hale-bopp, or whatever the trend of the day is. Hate to say it, but I think that it is reactions like this that stand in the way of real scientific progress. You shouldn't be afraid of science, it is merely a way to learn and digest the information around us in a logical and common-sensical way.
Deitheres - Master of... er... something.
-- .sig files go when they die?
Child: Mommy, where do
Mother: HELL! Straight to hell!
I've never been the same since.
Re:warning label (Score:1)
Ok, I realize that eating excessive amounts of beans can cause some big bangs, but I don't really think that they're of a cosmic scale.
Re:Who are the Authors of that Piece? (Score:1)
OK ppl. - reality check time (Score:1)
Honestly, some people have no decency. That the name of the finest theoretical physicist of our time should be attached to something like this is simply nauseating.
Re:Rubbish! (Score:1)
I'm sure the same thing has happened in the current situation. Unfortunately, the RHIC folks don't have the luxury of a super-duper-secret classification to protect them from the scientifically illiterate press.
Well... (Score:1)
Re:certainty and artificial black holes (Score:1)
===
-Ravagin
already happened? (Score:2)
I'm not suggesting that everyone should panic about RHIC, but trying to write it off as old hat isn't the appropriate response either.
Gravity is still related to mass. (Score:1)
While most of the posts here have been silly, I would like to point out that as best I can remember, the pull (Gravity) of a black whole is still related to its mass. Read: Black hole's have infinite density, not infinite mass. So say you converted 1 gram of matter into a black hole, it still would only have 1 gram's worth of pull. So the world wouldn't just instantly get sucked into oblivion.
However, this tiny black hole would tend to fall, as all things near the Earth do, and it would consume any matter it came in contact with, namely the ground, the mantle, the core, bit by bit, an atom at a time. In fact the mass of the earth is so small that the size of the black whole, probably would never get big enough to consume more than an atom at a time. It could conceivebly consume the whole planet assuming it had a stable orbit, as this thing would orbit the the center of the Earth, while passing though the Earth. Now a stable orbit isn't likely to form from a black hole created in the described manner. So, when enough mass is accumulated, the elliptical orbit will toss this thing far enough into space that the Sun's gravity will get ahold of it. In which case it would begin eating the Sun, and anything else in its orbit. The same process would likely happen there, and eventually it would be tossed out of our solar system, to go eat Alpha Centari or something else. Of course it may just eat everything, but it would still take a while.
Re:Someone really smart may be able to answer this (Score:1)
Re:wrong (Score:1)
-- .sig files go when they die?
Child: Mommy, where do
Mother: HELL! Straight to hell!
I've never been the same since.
Re:In defense of my posting... (Score:1)
Oh my, do we have a logical fallacy here? Why yes, boys and girls. It's our old friend, the argumentum ad hominem. Just because authority figures screwed up in the past (and in Challenger's case, it was bureaucrats who pushed the launch; the engineers, I believe, knew it probably wasn't safe to launch the shuttle), doesn't mean we can discount what they say now.
Mister Attack,
I think it's time to review your notes. This is not an ad hominem. The point is that experts are not infallible. Nowhere is it claimed that the experts are always wrong or that their opinions (in their respective fields, of course) are not more valid than those of others (i.e. not experts). All that is claimed is that the experts sometime make mistakes. In the case of the anhililation, even the smallest possibility of a mistake is too great. That was the point, and it is valid.
In other words, it is a proof by counterexample. I'll let you figure out the details.
Re:Logical fallacy. (Score:2)
Actually, a lot of people do take these seriously. I, for example, do not drive a car in order to decrease everyone elses chance of (c), as I am a terrible driver.
The point in being concerned about small chances of global catastrophy is not that it's likely, it's that right now we have all of our eggs in one basket and we can't very well afford to go throwing rocks....
I don't think this one accelerator is a big deal, but the thought is important. Every day, we receive several gamma-ray emmisions from deep-space. Many of them do not seem to be associated with any detectable stellar phenomenon. What if these gamma-ray sources are what's left of some world where a researcher said "I don't *think* this will cause a kilogram of matter to totally convert"? I haven't done the math, so I don't know how much matter would have to convert before you saw the kind of gamma-ray emmisions that we detect, but I suspect it's much less than an earth-size planet....
These are important things to think about. Even if we decide that it's more important to discover the nature of the universe than to avoid a little risk, we should consider what risk it is that we're not avoiding.
It's all a lie (Score:2)
Debunking the fear (Score:3)
- The creation of runaway black holes. It is true, if you cram enough matter into a small enough volume, you may reach the density required to form a Schwarzchild-like (or, if you put some English on the particles, and some charge, Kerr-Newman) black hole. However, the Chicken Littles who worried so intensely about this phenonmenon failed to account for something simple: Hawking radiation, that is, black holes evaporate. The larger the black hole, the slower the evaporation, in contradiction to common sense. Little-bitty holes go "poof!" in a flash of radiation and heavy particles. Anyway, the aforementioned CLs (Chicken Littles) failed to do a calculation out of, say, _Black Holes: The Membrane Paradigm_, in the section under "Evaporation of Black Holes In A Thermal Bath." It's basic differential equations, not that bad. I haven't gone through them myself, but I don't exactly sweat the announced end of the world, either.
- Strange matter. A very, very hypothetical possible byproduct (and from where they get the idea that it might be produced, I don't know) of certain collisions between selected particles would produce "strangelets," that is, baryonic matter like our nuclei, but with a non-zero strangeness (a quark property). Add hypothetical to hypothetical, strangelets can convert normal matter to strangelets and dump off energy. Again, the fear of a chain reaction. Once again, they overlooked the fact that strangelets only convert free neutrons. They can't even convert neutrons inside nuclei. Now, with a mean lifetime of approximately one thousand seconds, you just don't have a lot of free neutrons floating around. You'd have to work to create these hypothetical strangelets, hope that you'd get the conversion, and then build an entirely extra particle accelerator to funnel a beam of pure neutrons at your target. Not bloody likely.
Since most of the people doing the Chicken Little routine have doctorates, they should be ashamed. All of the data I have mentioned arises from my occasional prowls through the Web on odd topics and not much more than a light understanding of black holes. No good excuse exists for their collective oversight, and one might almost imagine that it is deliberate. "No such thing as bad publicity," goes the cliche, and I'm fairly sure that most of the remarks were made by second-raters with flagging careers who would like a little extra grant money.Re:Probability... (Score:2)
If anyone ever told you an event had probability zero and it did occur, they were an idiot.
Sorry, this will probably be rated as flamebait, but I can't stand when people who don't understand probability and statistics write it off as bullshit simply because they don't understand.
I strongly recommend the book Innumeracy by John Allen Paulos to anyone who has a problem with statistics. Maybe it won't teach you the subject in great detail, but it WILL show you how easily you can be ripped off by not understanding statistics. (Good read even if you think you already know.)
Sorry about the rant, but I come from a profession where manipulation and fabrication of figures (as is done by marketers to attract the public) would quickly end any prospects of future employment.
small but non-zero probabilities (Score:2)
As we begin to control greater energies, we seem to be entering a time when some scientific experiments will entail small, but non-zero, risk to people in the area, maybe even to humanity at large.
How small of a probability of disaster does it take before we can justify a certain amount of risk, and how do we estimate the probability of disaster without a large number of trials?
For instance: IIRC, pre-Challenger the official estimates on the Space Shuttle having a fatal accident were supposed to be something like one in a million. (My copy of What Do You Care What Other People Think? is at home, feel free to correct me on the real number.) How do you get that estimate? Best way would be to launch a million times and see what happens, but that's hardly practical. Instead it was based on engineering knowledge of well-understood physical principals, materials, and techniques. But it was completely wrong, extrapolation on top of extrapolation without even a propagation of errors. How much worse are our chances of predicting the risks of new techniques, new materials, even new physics?
Of course, the fine and noble folks onboard the shuttle knew that there was a risk, and volunteered to take it. What about "innocent" bystanders? The probability of a fatal accident during the Cassini launch or flyby may have been one in a million (or, it may have been much greater - NASA's "Cassini Mission False and True" [nasa.gov] says "the navigation accuracy of NASA spacecraft is better than 20 km." Or is that 20 miles?), but it was never non-zero. No launch has a non-zero risk - there's some small chance of a chain of malfunctions that crashes the thing into someone's house. How small do we have to get the risk to justify the experiment?
I'm not going to lose any sleep over the Brookhaven work - given what we know about cosmic rays, I'd say the risk is greater that I'll be hit by a metorite than that there will be any problems there. But the questions of risk to the public will remain.
Re:Alright...what is "strange matter"? (Score:3)
The fermions that feel the strong force are called the quarks and are individually named up, down, *strange* (so called because it wasn't expected at the time it was discovered), charm, bottom and top. The gluons (bosons for the strong force) interact very strongly with both the quarks and each other to such a degree that the quarks are actually bound together (nobody has ever experimentally observed a free quark) into groups of either three or two quarks, like the proton (two ups and a down) and the neutron (two downs and an up).
Strange matter is a grouping a quarks that include the strange quark. The reason why you haven't heard about strange matter before (but have heard about neutrons and protons I hope
The idea behind Stranglets is that the strange quark may actually form bound states that are energetically favourable, but that these states take a lot of energy to form (actually ripping the current bound states appart and re-arranging them is hard, but once you do it the state has lower energy). So RHIC might have a high enough energy to form them at which point they would start converting evreything they touch into stranglet including big particle accelerators, planets etc..
This idea just seems to be plain wrong. The calculation that the idea is based on is dubious, and as mentioned previously, if such energetically favourable states *could* be formed it's hard to see why they haven't already be formed as cosmic rays interact with the upper atmosphere.
So, there you go, I'm almost 99% certain that RHIC won't destroy the planet. What more could you ask for?
Re:Low probability and no evidence (Score:2)
--
Deja Moo: The feeling that
Small Black Holes (Score:2)
All black holes undergo a quantum mechanical equivilant of evaporation. The smaller they are, the quicker they evaporate their contents into the visible universe as radiation. The basic idea behind the theory is quantum tunneling. If you compress something into a very very small volume, and as the volume approaches the Plank scale, the probability that particles trapped (in the classical sense) inside this volume can exist outside it will increase. This happens because the Debroglie wavelength of the particles doesn't change.
Now, in order to create a black hole with the small ammount of matter inside the collider, you would be looking at a Shwartzchild radius in the Plank scale. Somewhere in the order of 10^-30 m. (Maybe someone can check me on this with the approximation R=GM/c^2....this value may be too low).
Anyway, at this scale the black hole would vanish in an incredibly short period of time. Far too short to vacuum cleaner the Earth into a blackhole spacetime.
Large black holes on the other hand evaporate on scales greater than the age of the universe. Something on the order of > 10^100 years.
Bones, do you know what you've done ? Pretty soon they'll want a peice of OUR action !!!
Star Trek, "A Peice of the Action"
Re:In defense of my posting... (Score:2)
Which could be construed as undermining your original argument. Still, when faced with scientist X saying it's safe, and scientist Y saying it isn't, you don't always have the grace of an easy decision. Not all the "engineers" were objecting to the launch. And the attitude at NASA was very much post hoc ergo propter hoc.
The point I'm trying to make is roughly: any bureaucrat/politician/careerist scientist may choose to demonstrate a 1 in 1^n probability of risk. But are they correct, or are they cooking the numbers? Do we assume that we know enough to calculate these things with necessary precision? Before Trinity (to return to your original example) there had been not a single nuclear explosion in all of human history. With no experimental data, how could the Manhattan Project experts who calculated the risk of "igniting the atmosphere" really be certain? They couldn't. They could make educated guesses, and they did, and fortunately they were right.
My deeper point here is that we are at a point in human capability where we can make things -- quark guns, atom bombs -- that have potentially devastating side-effects. Therefore, a minor amount of prudence and forethought seems like a small price to pay for peace of mind.
----
Lake Effect [wwa.com], a weblog
Re:Life is a quantum crapshoot... (Score:2)
a six-year old girl with an iMac.
"The number of suckers born each minute doubles every 18 months."
Someone call Gary North! (Score:2)
(Don't get it? http://www.garynorth.com [graynorth.com]
There's a funny commentary at http://www.garysouth.com [garysouth.com], and another supposedly at http://garynorth.shadowscape.net [shadowscape.net], which appears to be down now :(. )
Black holes (Score:2)
What was theorized that we might see left over from the Big Bang is quantum black holes, of a few million or billion tons (the mass of a big iceberg or small asteroid). So far there is no evidence for their existence.
--
Deja Moo: The feeling that
Logical fallacy. (Score:4)
The idea that we are going to destroy the world with the RHIC is absolutely ridiculous. I remember reading that a large number of physicists thought the first nuclear weapon would ignite the atmosphere, destroying all life on Earth. Didn't happen.
This is a logical fallacy known as post hoc ergo propter hoc. Just because we haven't destroyed the earth in the past doesn't mean we can't do it.
Now we have a _journalist_ - not even a Ph.D. in physics - claiming that we're going to create a black hole with the RHIC.
Ad hominem. In fact, objections have been raised within the scientific community. They have been taken seriously enough to be reviewed by the laboratory [bnl.gov]. They disagreed, of course.
This is a remote possibility, to say the least - collisions at much higher energy than this happen in our upper atmosphere daily without destroying us. But assuming for a moment that a black hole is created, what happens? The answer is simple: it will evaporate.
At last a real argument. I happen to agree with you in principle; I'm not going to lose sleep over these experiments. But I don't think that going around shouting "rubbish!" at people is the way to make your point. There are valid scientific questions to be raised here, and while the field of high-energy physics may be dominated by people who believe it's perfectly safe, the objections do not come from left field. It may not be this experiment, but I would not rule out the possibility that in the near future we could devise experiments that would be capable of creating (say) a microscopic black hole.
I'd be more worried about ballistic nukes from China.
Most people should worry about a) heart disease, b) lung cancer, and c) an auto accident, in roughly that order. Since we all know that very few people give those very real dangers any thought at all
No, I don't believe RHIC is going to kill us all. But can we indeed come up with an experimental device that could? Most certainly. And human history is filled with enough follies by people who "know what they're doing" (say, Challenger) that I don't put all my trust in the intelligentsia here. The only safeguard is an atmosphere of collegiality where objections such as the one raised against RHIC are treated seriously and given due consideration in a peer review process.
That has happened, and has completed. It's only afterwards that the media really got hold of the story, and as they always do, they report it as if it were two equally valid political positions. Don't give in to the hysteria by treating all such objections with contempt.
----
Lake Effect [wwa.com], a weblog
"strange matter" (Score:2)
It holds a relationship to normal matter something akin to antimatter's, although it is not antimatter (there is "normal" strange matter and "antimatter" strange matter). Basically, it looks like normal matter but isn't made up of the same kinds of subparticles. I think that strange matter in general is nowhere near as stable as normal matter.
----
Lake Effect [wwa.com], a weblog
Re:already happened? (Score:2)
No, it's true.
They are not claiming that these conditions haven't existed since the big bang. (That would be absurd.) This will simply be the first time such conditions have been recreated in a lab.
Please, reread the bit about cosmic rays. Every day the earth is bombarded by millions (I'm way underestimating here) of cosmic ray particles so energetic that they laugh heartily at the feeble attempts of Brookhaven to match them.
When we do it in a lab, we can be there to watch. But as far as the earth is concerned, it is very old hat indeed.
Re:Life is a quantum crapshoot... (Score:2)
Re:Art Bell guest (Score:2)
Sorry, but you've been had.
...phil
warning label (Score:2)
Grandpa speaks out... (Score:3)
These confounded kids today with their theory of evolution, beowulf clusters, open-source operating systems. MAMBY PAMBY! HUH! In my day, Mr. Watson told us there was a world market for four or five computers and we liked it.
Well, I don't think that the world is gonna end thanks to that darn Scooby Doo and those darn meddlin' kids.
Good journalism (Score:2)
It's nice to see a sensible article responding to all too common poorly researched media rubbish.
The sad thing is that it seems people would rather buy sensationalist fiction than (IMHO interesting)
facts. Papers only report what their buyers want
to hear.
I think experimental physics is interesting enough without wildly claiming we're going to risk the
universe every few months. (I expect we'll *really* get onto that kind of dangerous stuff in a decade or two)
Who are the Authors of that Piece? (Score:2)
Personally, I agree with them, in my limited knowledge of particle physics, especially about the idea that collisions of this type and energy (and MUCH higher energy) happen frequently in nature, but I would feel much more comfortable if this was from a truly independant source.
The nagging question is: What if it DOES happen rarely in the uncontrolled collisions of cosmic rays in nature. How would we ever know that a world had been destroyed by conversion to strange matter or converted into a black hole? Sure there is a lot of catastrophic, random badness that happens in the universe, but is such an accident any MORE likely to happen in a controlled environment?
There is just something far to elegant about the idea that this type of experiment is just the reason there are no signs of intelligent life in the universe...
Eh, so what? (Score:2)
The Brookhaven effort has one thing going for it, and that is observability. The collisions will be nice and conveniently placed so we can analyze what's going on in them and get data; to get anything new about quark-gluon plasmas we're going to have to have detectors right on top of the action. If it weren't for that, we'd be far better off just watching what Nature throws at us for free.
--
Deja Moo: The feeling that
Re:Ah...I needed a good laugh. (Score:2)
My life will end in 52d:5h:22min... (Score:3)
Personally, I almost wish a black hole would sweep down from that big bad particle accelerator and wipe out earth, just so we could stop having to read these ignorant doomsayers (Fred Moody) predict the end of the world....how's that for recursive irony?
Re:Forever Peace (Score:2)
Good book, too, though not as good as Forever War.
Jet forming does not affect the conclusion. (Score:2)
The Moon would take a hammering of about 1e19 J/m^2 on the Earth-facing side. The entire near side would also be vaporized, along with every trace of human activity on the Moon. It would also receive a hell of a kick. I don't know if it would hold together or be blown to pieces, but I'm absolutely certain that it would not remain in orbit around the former Earth.
Mars, at some 40 million miles away at closest approach, would get about 1/40000 as much flux as the Moon at the worst. That's still on the order of a megaton per square meter! Just face it, if any planet in the Solar system went down a black hole, the entire neighborhood would be a pretty unhealthy place to be for the duration.
--
Deja Moo: The feeling that
The right answer(s) (Score:2)
The right answer is that space is almost empty, so the black hole cannot grow quickly. (but see below for more)
A black hole has the same gravitational pull as a star of the same mass would. So, if our Sun miraculously became a black hole, it could not suck in the Earth. Black holes are special because you can get really close to them. Since gravity decreases as the distance squared, small distance equals strong gravity.
Radiation is not a significant factor. Only very small black holes radiate significantly enough to matter. A solar-mass black hole would take 10^67 years to evaporate... alienmole had it right above.
In a high-density environment, black holes do grow. Namely, in the center of galaxies we see black holes that can be like a million or 10 million times the mass of the Sun. Ones which are actively feeding (on gas clouds, stars, etc) may explain quasars (the brightest sustained light sources in the universe).
The Milky Way almost certainly has a pretty decent sized black hole in the center, so our galaxy may once have hosted a quasar.
M87 [nasa.gov] has a somewhat active one now. See http://antwrp.gsfc.nasa.gov/a pod/index/blackhole.html [nasa.gov] for more observational evidence of black holes.
Re:Whats the energy? (Score:2)
There is lots of scientific information about RHIC here [bnl.gov]. Follow the links to "Documentation" and "RHIC Design Manual" for detailed information about its motivation and specifications.
Life is a quantum crapshoot... (Score:2)
But you can be certain of one thing -- there will be a TV movie made within six months about a black hole created by clueless scientists that threatens to destroys the earth. Destroy, that is, until the hero scientist that no-one listened to comes up with a magic black hole plug...
Jack
Rubbish! (Score:4)
Re:certainty and artificial black holes (Score:2)
A -much- more devastating weapon would be created if there was an effective way to tunnel, in a controlled manner. Link two quantum-scale wormholes together, get one into the target area and inflate the tunnel. Whatever you lobbed through the tunnel would arrive at the other mouth of the wormhole, without apparently traversing any intermediate space. It would be impossible to shield against, and impossible to detect.
Monkey Science (Score:2)